ADTRAN 1200051L6 - Manual (Page 74)

Chapter 6. Configuration
60 ISU 2x64 Dual Port ISDN Service Unit User Manual 61200051L1-1D
The primary usage for SAP is general purpose asynchronous rate
adaptation in a dial-up or leased environment. SAP only oper-
ates on a 64 kbps data link. Figure 6-21 illustrates the menu path
for selecting SAP.
FALLBACK
The FALLBACK asynchronous rate adaptation protocol provides
the capability to automatically establish calls with other ISDN
terminal adapters and Switched 56 DSUs, as well as other ISUs
using a single configuration. The ISU 2x64 must be optioned as
follows for FALLBACK operation:
1. Any asynchronous bit rate up to 115.2 kbps which is support-
ed by the DTE.
2. Flow control must be enabled and supported by the DTE.
FALLBACK supports the following protocols based on the Call
Type: BONDING mode 1, V.120, and T-Link. Figure 6-21 illus-
trates the menu path for selecting FALLBACK.
When answering calls, the ISU 2x64 uses the incoming call type
to determine which rate adaptation protocols to support.
Table 6-A
Rate Adaptation Protocols
Call Type
Rate Adaption Protocols
Supported
Typical Units Supported
Data 64 k Bonding mode 1 ISUs
V.120 ISDN TAs
PPP async-sync PPP compatible bridges/routers
Data 56 k BONDING mode 1 ISUs
V.120 ISDN TAs
PPP async-sync PPP compatible bridges/routers
T-Link 2-wire Switched 56 DSUs